river landscape

physical processes

weathering processes

mechanical

chemical

biological

rainwater slightly acidic. acid reacts with minerals in rocks and dissolves them

  1. water fills a crack in the rock
  1. water freezes and crack is widened
  1. repeated freeze-thaw action increases size of crack until block of rock breaks off
  1. looses blocks of rock are called scree

roots grow into cracks and split apart

mass movement

sliding

tock, weathered or eroded material or earth moves down a slope. gravity pulls weakened material quickly downwards

slumping

where river erodes bottom of valley slope, making it stepper. material above slides downwards, particularly if it's saturated with rainwater

erosion

hydraulic action

force of water on bed and banks of river removes material

solution

some rock minerals dissolve in river water

abrasion

material carried by river rubs against bed and banks and wears them away

transport and deposition

transport is way in which river carries eroded material or load

traction

large boulders rolled along river bed

saltation

smaller pebbles bounced along river bed, picked up then dropped as river flow changes

suspension

finer sand and silt particles carried along in flow, giving river brown apperance

solution

some minerals (e.g. chalk) dissolved in water and carried along in flow, they can't be seen